The concert, which took place in Ostritz in the state of Saxony on Saturday, featured two bands from “the right-wing scene” and had drawn an audience of “several hundred”, Görlitz police said in a statement.
Officers stationed outside intervened after hearing shouts of “Sieg Heil” (Hail Victory) coming from the venue at 11:20pm. The gig was brought to an end and the building was emptied shortly after 1am.
Several witnesses also reported hearing the chants.
Federal authorities have opened an investigation, Görlitz police added.
Under German law, using Nazi-era slogans or publicly displaying swastikas and other Nazi symbols is illegal.
The town of Ostritz, near the border with Poland, regularly hosts far-right concerts that are often controversial.
Last April, hundreds of neo-Nazis gathered in the remote town for a festival timed to coincide with Hitler's birthday.
Concern has grown in Germany that the rise of the anti-Islam, anti-immigrant Alternative for Germany party (AfD) in recent years has emboldened the far-right and the neo-Nazi scene.
The fatal stabbing of a German man allegedly by asylum seekers in the city of Chemnitz in August, also in Saxony state, triggered far-right street protests at which some demonstrators performed the straight-armed Hitler salute.
A 34-year-old man was later jailed for five months for making the illegal greeting.